Endoscopic imaging system

ABSTRACT

An endoscopic imaging system includes a reusable control cabinet having a number of actuators that control the orientation of a lightweight endoscope that is connectable thereto. The endoscope is used with a single patient and is then disposed. The endoscope includes an illumination mechanism, an image sensor and an elongate shaft having one or more lumens located therein. A polymeric articulation joint at the distal end of the endoscope allows the distal end to be oriented by the control cabinet. The endoscope is coated with a hydrophilic coating that reduces its coefficient of friction and because it is lightweight, requires less force to advance it to a desired location within a patient.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.10/406,149, filed Apr. 1, 2003, the disclosure of which is expresslyincorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to medical devices in general andtherapeutic and diagnostic endoscopes in particular.

BACKGROUND OF THE INVENTION

As an aid to the early detection of disease, it has become wellestablished that there are major public health benefits from regularendoscopic examinations of internal structures such as the esophagus,lungs, colon, uterus, and other organ systems. A conventional imagingendoscope used for such procedures comprises a flexible tube with afiber optic light guide that directs illuminating light from an externallight source through a lens at the distal end of the endoscope whichfocuses the illumination on the tissue to be examined. An objective lensand fiber optic imaging light guide communicating with a camera at theproximal end of the scope, or an imaging camera chip at the distal tip,transmit an image to the examiner. In addition, most endoscopes includeone or more working channels through which medical devices such asbiopsy forceps, snares, fulguration probes, and other tools may bepassed.

Navigation of the endoscope through complex and tortuous paths iscritical to success of the examination with minimum pain, side effects,risk or sedation to the patient. To this end, modern endoscopes includemeans for deflecting the distal tip of the scope to follow the pathwayof the structure under examination, with minimum deflection or frictionforce upon the surrounding tissue. Control cables similar to puppetstrings are carried within the endoscope body and connect a flexibleportion of the distal end to a set of control knobs at the proximalendoscope handle. By manipulating the control knobs, the examiner isusually able to steer the endoscope during insertion and direct it tothe region of interest, in spite of the limitations of such traditionalcontrol systems, which are clumsy, non-intuitive, and friction-limited.Common operator complaints about traditional endoscopes include theirlimited flexibility, limited column strength, and limited operatorcontrol of stiffness along the scope length.

Conventional endoscopes are expensive medical devices costing in therange of $25,000 for an endoscope, and much more for the associatedoperator console. Because of the expense, these endoscopes are built towithstand repeated disinfections and use upon many patients.Conventional endoscopes are generally built of sturdy materials, whichdecreases the flexibility of the scope and thus can decrease patientcomfort. Furthermore, conventional endoscopes are complex and fragileinstruments which can frequently need expensive repair as a result ofdamage during use or during a disinfection procedure. To overcome theseand other problems, there is a need for a low cost imaging endoscopethat can be used for a single procedure and thrown away. The scopeshould have better navigation and tracking, a superior interface withthe operator, improved access by reduced frictional forces upon thelumenal tissue, increased patient comfort, and greater clinicalproductivity and patient throughput than those that are currentlyavailable.

SUMMARY OF THE INVENTION

To address these and other problems in the prior art, the presentinvention is an endoscopic video imaging system. The system includes amotion control cabinet that includes a number of actuators that controlthe orientation of an endoscope and an imaging system to produce imagesof tissue collected by an image sensor at the distal end of theendoscope. A single use endoscope is connectable with the controlcabinet and used to examine a patient. After the examination procedure,the endoscope is disconnected and disposed of.

The endoscope of the present invention includes a flexible elongate tubeor shaft and an illumination source that directs light onto a tissuesample. An image sensor and objective lens at or adjacent the distal endof the endoscope captures reflected light to produce an image of theilluminated tissue. Images produced by the sensor are transmitted to adisplay device to be viewed by an examiner. In one embodiment, theillumination source comprises one or more light emitting diodes (LEDs)and the image sensor comprises a CMOS solid state image sensor.

The endoscope of the present invention also includes a steeringmechanism such as a number of tensile control cables, which allow thedistal end of the endoscope to be deflected in a desired direction. Inone embodiment of the invention, a proximal end of the tensile controlcables communicates with actuators within the control cabinet. Afreestanding joystick controller generates electrical control signalswhich the control cabinet uses to compute signals to drive the actuatorsthat orient the distal end of the endoscope in the direction desired bythe examiner. In another embodiment of the invention, the distal end ofthe endoscope is automatically steered, or provided to the examiner,based on analysis of images from the image sensor.

In one embodiment of the invention, the endoscope includes a polymericarticulation joint adjacent its distal end that aids in bending thedistal end of the scope in a desired direction. The articulation jointis constructed as a number of live hinges integrated into a unifiedstructure of the required overall properties and dimensions. Tension ofthe control cables causes the live hinges of the articulation joint todeflect, thereby bending the distal tip of the endoscope. In oneembodiment of the invention, the articulation joint exerts a restoringforce such that upon release of a tensioning force, the distal end ofthe scope will straighten.

In an alternative embodiment, the articulation joint comprises a numberof stacked discs that rotate with respect to one another. Control cablespass through the discs and pull adjacent discs together to turn thedistal end of the endoscope.

In another embodiment of the invention, the endoscope has a variation instiffness along its length that allows the distal end to be relativelyflexible while the more proximal regions of the scope have increasedcolumn strength and torque fidelity so that a physician can twist andadvance the endoscope with greater ease and accuracy and with fewerfalse advances (“loops”). Variation in stiffness along the length can beprovided by varying the durometer of materials that comprise a shaft ofthe endoscope. Operator-controlled, variable stiffness can be providedby control cables that can be tightened or loosened to adjust thestiffness of the shaft. In yet another embodiment, the spacing betweenthe live hinges of the articulation joint is selected to provide avariation in stiffness along the length of the articulation joint.

In yet another embodiment of the invention, the endoscope is coveredwith a retractable sleeve that uncovers the distal end of the scopeduring use and extends over the distal end after the scope is removedfrom a patient.

In another embodiment of the invention, the scope is coated with ahydrophilic coating to reduce its coefficient of friction.

In another embodiment of the invention, the scope is retractable in alongitudinal direction. The distal end of the scope is extendable usinga spring, pull wires, bellows or the like to allow a physician to movethe distal tip without having to alter the position of the shaft of theendoscope.

In yet another embodiment of the invention, the endoscope includes aheat dissipating mechanism for removing heat produced by theillumination source and image sensor.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing aspects and many of the attendant advantages of thisinvention will become more readily appreciated as the same become betterunderstood by reference to the following detailed description, whentaken in conjunction with the accompanying drawings, wherein:

FIGS. 1A and 1B illustrate two possible embodiments of an endoscopicvideo imaging system in accordance with the present invention;

FIG. 2 illustrates further detail of an endoscope used in the imagingsystem shown in FIG. 1A;

FIG. 3A is a block diagram of a motion control cabinet that interfaceswith an imaging endoscope in accordance with one embodiment of thepresent invention;

FIG. 3B is a block diagram of a motion control cabinet that interfaceswith an imaging endoscope in accordance with another embodiment of thepresent invention;

FIGS. 4A-4D illustrate one mechanism for connecting the vision endoscopeto a motion control cabinet;

FIG. 5 is a detailed view of one embodiment of a handheld controller forcontrolling an imaging endoscope;

FIG. 6 illustrates one embodiment of a distal tip of an imagingendoscope in accordance with the present invention;

FIG. 7 illustrates one mechanism for terminating a number of controlcables in a distal tip of an imaging endoscope;

FIG. 8 illustrates an imaging endoscope having control cables routedthrough lumens in the walls of an endoscope shaft;

FIGS. 9A and 9B illustrate a transition guide that routes control cablesfrom a central lumen of an endoscope shaft to lumens in an articulationjoint;

FIGS. 10A and 10B illustrate the construction of a shaft portion of anendoscope in accordance with one embodiment of the present invention;

FIG. 11 illustrates one mechanism for providing a shaft having a varyingstiffness along its length;

FIGS. 12A and 12B illustrate an extrusion used to make an articulationjoint in accordance with one embodiment of the present invention;

FIG. 13 illustrates an articulation joint in accordance with oneembodiment of the present invention;

FIGS. 14 and 15 illustrate an extrusion having areas of a differentdurometer that is used to form an articulation joint in accordance withanother embodiment of the present invention;

FIGS. 16A and 16B illustrate another embodiment of an articulation jointincluding a number of ball and socket sections;

FIGS. 17A-17D illustrate various possible configurations of ball andsocket sections used to construct an articulation joint;

FIGS. 18A-18B illustrate an articulation joint formed of a number ofstacked discs in accordance with another embodiment of the presentinvention;

FIGS. 19A-19B illustrate a disc used to form an articulation joint inaccordance with another embodiment of the present invention;

FIGS. 20A-20B illustrate a disc used to form an articulation joint inaccordance with another embodiment of the present invention;

FIGS. 21A-21B illustrate a non-circular segment used to form anarticulation joint in accordance with another embodiment of the presentinvention;

FIG. 22 illustrates an endoscope having a braided member as anarticulation joint in accordance with another embodiment of the presentinvention;

FIG. 23 illustrates one possible technique for securing the ends of acontrol wire to a braided articulation joint;

FIG. 24 illustrates a shaft having one or more memory reducing wraps inaccordance with another embodiment of the present invention;

FIG. 25 illustrates a shaft including longitudinal stripes of a highdurometer material in accordance with another embodiment of the presentinvention;

FIGS. 26-29 illustrate alternative embodiments of a gripping mechanismthat rotates an imaging endoscope shaft in accordance with the presentinvention;

FIGS. 30A and 30B illustrate a retractable sleeve used with anotherembodiment of the present invention;

FIG. 31 illustrates one embodiment of a heat dissipating distal tip ofan endoscope in accordance with the present invention; and

FIGS. 32 and 33 illustrate alternative embodiments of a heat dissipatingdistal tip in accordance with the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

As indicated above, the present invention is an endoscopic video imagingsystem that allows a physician to view internal body cavities of apatient as well as to insert surgical instruments into the patient'sbody. An imaging endoscope used with the present invention issufficiently inexpensive to manufacture such that the endoscope can beconsidered a disposable item.

As shown in FIG. 1A, an endoscopic video imaging system 10 according toone embodiment of the present invention includes an imaging endoscope20, a motion control cabinet 50 and a handheld controller 80. Theimaging endoscope 20 has a distal tip 22 that is advanced into apatient's body cavity and a proximal end 24 that is connected to themotion control cabinet 50. As will be explained in further detail below,the motion control cabinet 50 includes a number of actuators thatcontrol a steering mechanism within the endoscope in order to change theorientation of the distal tip 22. A physician or their assistant usesthe handheld controller 80 to input control signals that move the distaltip 22 of the imaging endoscope 20. In addition, the motion controlcabinet 50 may include connections to sources of air/gas and a flushingliquid such as water for clearing the imaging endoscope. The motioncontrol cabinet 50 also includes imaging electronics to create and/ortransfer images received from an image sensor to a video display forviewing by a physician or technician.

In the embodiment shown, the imaging endoscope 20 also includes abreakout box 26 that is positioned approximately midway along the lengthof the endoscope. The breakout box 26 provides an attachment point for avacuum bottle 40 that collects liquids from a lumen within the imagingendoscope. The vacuum bottle 40 is controlled by a vacuum valve 28 thatis positioned on the breakout box 26. Alternatively, the valve can bepositioned within the motion control cabinet 50 and controlled from thehandheld controller 80.

If desired, the handheld controller 80 can be secured to the breakoutbox 26 such that the two units can be moved as one if desired. Uponcompletion of a patient examination procedure, the imaging endoscope 20is disconnected from the motion control cabinet 50 and disposed of. Anew imaging endoscope 20 is then connected to the motion control cabinet50 for the next examination procedure to be performed.

The embodiment shown in FIG. 1A is a “parallel” configuration wherebythe endoscope 20 and handheld controller 80 are separately plugged intodifferent connectors of the motion control cabinet 50. This parallelconfiguration allows one operator to handle the endoscope while anotheroperator can handle the handheld controller 80. Alternatively, thehandheld controller 80 may be secured to the endoscope 20 such that asingle operator can control both. FIG. 1B illustrates a “serial”configuration of the invention. Here, the imaging endoscope 20 isconnected to the motion control cabinet 50 through the handheldcontroller 80.

FIG. 2 shows further detail of one embodiment of the imaging endoscope20. At the proximal end of the endoscope is a low torque shaft 24 and aconnector 34 that connects the endoscope 20 to the motion controlcabinet 50. Distal to the breakout box 26 is a higher torque shaft. Atthe distal end of the endoscope 20 is the distal tip 22 that includes alight illumination port, an image sensor, an entrance to a working lumenand a flushing lumen (not shown). Proximal to the distal tip 22 is anarticulation joint 30 that provides sufficient flexibility to the distalsection of the shaft such that the distal tip 22 can be directed over anangle of 180 degrees by the steering mechanism.

As discussed above, the endoscope 20, in accordance with one embodimentof the invention, has a higher torque shaft at the distal section of theendoscope and a lower torque shaft at its proximal end. The breakout box26 positioned along the length of the endoscope shaft can be used as ahandle or gripper to impart rotation of the distal end of the endoscopeduring a medical examination procedure. The higher torque portion of theshaft transfers rotational motion that is imparted at a locationproximal to the distal tip in order to guide the distal tip of theimaging catheter. The low torque shaft portion of the imaging catheterdoes not transfer torque as well and can twist when rotational motion isapplied.

In use, the physician can insert a medical device such as a biopsyforceps, snare, etc., into a connector 32 found on the breakout box 26that leads to a working channel lumen in the endoscope. In alternateembodiments, the entrance to the working channel lumen may be positionedfurther towards the proximal end of the endoscope.

FIG. 3A is a block diagram of the major components included within oneembodiment of the motion control cabinet 50. The motion control cabinetis preferably positioned on a cart that is wheeled near a patient priorto an examination procedure. The motion control cabinet is connected toa source of electrical power, either A.C. mains or a battery, as well asto a source of insufflation gas and irrigation liquid. Inside the motioncontrol cabinet 50 is a controller interface 52 that is connected to thehandheld controller 80 and receives control signals therefrom. To changethe orientation of the distal tip of the imaging endoscope, the controlsignals are received from a directional switch in the handheldcontroller 80. The control signals are supplied to a servo motorcontroller 54 that in turn controls a number of actuators, such as servomotors 56 a, 56 b, 56 c, 56 d. Each of the servo motors 56 a-56 d isconnected to one or more control cables within the imaging endoscope.Motion of the servo motors 56 a-56 d pulls or releases the controlcables in order to change the orientation of the distal tip 22 of theimaging endoscope 20. Although the embodiment shown in FIG. 3A showsfour servo motors and control cables, it will be appreciated that feweror more servo motors and corresponding control cables could be used tomove the distal tip. For example, some imaging endoscopes may use threecontrol cables and three associated servo motors.

Also included in the motion control cabinet 50 is a power source 58 thatprovides electrical power to a light source such as a number of lightemitting diodes (LEDs) at the distal end 22 of the imaging endoscope.Alternatively, if the imaging catheter utilizes an external lightsource, then the motion control cabinet can include a high intensitylight source such as a laser or Xenon white light source that supplieslight to a fiber optic illumination guide within the imaging endoscope20 in order to illuminate an internal body organ. The power source 58may be controlled by control signals received from the handheldcontroller 80 when the user desires to activate the light source.

An imaging electronics board 60 captures images received from an imagesensor (not shown) at the distal end of the imaging endoscope. Theimaging electronics board 60 can enhance the images received or canprovide video effects such as zoom, color changes, highlighting, etc.,prior to display of the images on a video display (not shown). Images ofthe tissue may also be analyzed by the imaging electronics board 60 toproduce control signals that are supplied to the servo motor controller54 in order to automatically steer the distal tip of the endoscope aswill be discussed in further detail below. Images produced by theimaging electronics board 60 may also be printed on a digital printer,saved to a computer readable media such as a floppy disk, CD, DVD, etc.,or a video tape for later retrieval and analysis by a physician.

Finally, the motion control cabinet 50 includes valves 70 that controlthe delivery of insufflation air/gas to insufflate a patient's bodycavity and an irrigation liquid to flush out a body cavity and/or cleanthe imaging light source and image sensor at the distal end of theendoscope. The insufflation air/gas and irrigation liquid are connectedto the imaging catheter via a connector 38 that connects to anirrigation/insufflation lumen of the imaging endoscope 20. In oneembodiment of the invention, the irrigation and insufflation lumen arethe same lumen in the imaging catheter. However, it will be appreciatedthat separate irrigation and insufflation lumens could be provided ifdesired and if space in the endoscope permits.

FIG. 3B illustrates another embodiment of a motion control cabinet 50Athat is similar to the cabinet shown in FIG. 3A. The motion controlcabinet 50A includes a vacuum valve 71 that controls vacuum delivered toa vacuum collection bottle 40. A vacuum line 73 connects to a vacuumlumen within the imaging endoscope 20. The vacuum valve 71 is controlledfrom the handheld controller 80.

FIGS. 4A-4D illustrate one mechanism for securing the proximal end ofthe imaging endoscope to the control cabinet 50 prior to performing anendoscopic examination. The control cabinet 50 includes a connector 34Ahaving a number of shafts 57 that are driven by the servo motors 56shown in FIGS. 3A and 3B. Each shaft 57 is shaped to be received in acorresponding spool on which the control cables are wound. Also includedin the connector 34A are connections to the insufflation and irrigationvalves 70 and vacuum valve 71 to provide air, water and vacuum to theendoscope.

FIGS. 4A and 4B illustrate one possible connector 34 found at theproximal end of the endoscope 20 for securing the endoscope to themotion control cabinet 50. The connector 34 includes a number ofthumbscrews 77 or other quick release mechanisms that allow theconnector 34 to be easily secured to the connector 34A on the motioncontrol cabinet. As shown in FIG. 4C, the connector 34A includes anumber of spools 79 about which the control cables are wound. Each spoolis preferably threaded or grooved to prevent the control cables frombinding on the spool during use. A cover may surround a portion of thespool to keep the control cables against the spool and to aid insupporting the spool within the connector 34. In one embodiment of theinvention, the spools are prevented from rotating when the connector isnot engaged with the motion control cabinet 50 by brakes 81 having pinsthat fit within corresponding slots in the spool. Once the connector 34is mounted to the motion control cabinet 50, the brakes 81 aredisengaged from the spool such that the spool can be moved by the servomotors. Electrical connections for the light source and image sensor aswell as connections to the air and water valves can be found on thesides of the connector or on the rear face of the connector 34 to engagethe valves, as shown in FIG. 4A.

FIG. 4D illustrates a cross-sectional view of a shaft 57 fitted within aspool 79. The shaft 57 is supported by a cylinder 59 having a spring 61therein such that the shaft 57 is free to move within the cylinder 59.The cylinder 59 is directly coupled to the servo motors within themotion control cabinet. The spring 61 allows the shaft 57 to float suchthat the shaft can more easily align and engage the mating surface ofthe spool 79.

Upon insertion of the shaft 57 into the spool 79, the brake 81 isreleased, thereby allowing the spool 79 to be moved by rotation of thecylinder 59. In some instances, the brake 81 may be omitted, therebyallowing the spools 79 to freely rotate when the connector 34 is notengaged with the motion control cabinet 50.

FIG. 5 illustrates various controls located on the handheld controller80 in accordance with one embodiment of the invention. The handheldcontroller 80 includes a controller body 82 that, in the parallelembodiment of the invention, is coupled to the motion control cabinet 50by an electrical cord 84, a wireless radio frequency channel, aninfrared or other optical link. If the connection is made with anelectrical cord, a strain relief 86 is positioned at the junction of theelectrical cord 84 and the body 82 of the controller to limit thebending of the electrical wires within the electrical cord 84. In theserial embodiment of the invention, the connection of the handheldcontroller 80 to the motion control cabinet 50 is made with a conductorthat includes both the wires to transmit signals to the motioncontrollers and imaging systems, as well as a lumens to carry theinsufflation air/gas and irrigation liquid. In addition, the controlcables of the endoscope engage cables connected to the actuators in themotion control cabinet through the handheld controller 80.

Positioned in an ergonomic arrangement on the handheld controller 80 area number of electrical switches. An articulation joystick 88 or othermulti-positional device can be moved in a number of positions to allowthe physician to orient the distal tip of the imaging endoscope in adesired direction. In order to guide the imaging endoscope manually, thephysician moves the joystick 88 while watching an image on a videomonitor or by viewing the position of the distal tip with another medialimaging technique such as fluoroscopy. As the distal tip of theendoscope is steered by moving the joystick 88 in the desired direction,the physician can push, pull and/or twist the endoscope to guide thedistal tip in the desired direction.

A camera button 90 is provided to capture an image of an internal bodycavity or organ in which the imaging endoscope 20 is placed. The imagescollected may be still images or video images. The images may beadjusted for contrast or otherwise enhanced prior to display or storageon a recordable media.

An irrigation button 92 activates an irrigation source to supply aliquid such as water through an irrigation lumen of the imagingendoscope. The liquid serves to clean an image sensor and the lightsource at the distal end of the endoscope as well as an area of the bodycavity. An insufflation button 94 is provided to activate theinsufflation source within the motion control cabinet 50 to supplyair/gas through a lumen of the catheter. The supply of the insufflationgas expands portions of the body cavity around the distal tip of theendoscope so that the physician can more easily advance the endoscope orbetter see the tissue in front of the endoscope.

In one embodiment of the invention, the handle 82 also includes a thumbscrew 96 for securing the handheld controller 80 to the breakout box 26as indicated above. A corresponding set of threads on a breakout box 26receive the thumb screw 96 in order to join the two parts together. Oneor more additional buttons 98 may also be provided to activateadditional functions such as recording or printing images, adjustinglight intensity. activating a vacuum control valve, etc., if desired.

The endoscope of the present invention may also be steeredautomatically. Images received by the imaging electronics 60 areanalyzed by a programmed processor to determine a desired direction ororientation of the distal tip of the endoscope. In the case of acolonoscopy, where the endoscope is advanced to the cecum, the processorcontrols the delivery of insufflation air/gas to inflate the colon, theprocessor then analyzes the image of the colon for a dark spot thatgenerally marks the direction in which the scope is to be advanced. Theprocessor then supplies control instructions to the servo controller 54such that the distal tip is oriented in the direction of the dark spotlocated.

In other modes, a processor in the motion control cabinet causes thedistal tip of the endoscope to move in a predefined pattern. Forexample, as the scope is being withdrawn, the distal tip may be causedto move in a search pattern such that all areas of a body cavity arescanned for the presence of disease. By using the automatic control ofthe distal tip, a physician only has to advance or retract the scope toperform an examination.

As will be described in further detail below, the imaging endoscope 20generally comprises a hollow shaft having one or more lumens formed ofpolyethylene tubes which terminate at the distal tip 22. As shown inFIG. 6, one embodiment of a distal tip 110 comprises a cylinder having adistal section 112 and a proximal section 114. The proximal section 114has a smaller diameter than the diameter of the distal section 112 inorder to form a stepped shoulder region. The diameter of the shoulder isselected that shaft walls of the endoscope can seat on the shoulderregion to form a smooth outer surface with the distal section 112. Thedistal face of the distal tip 110 includes a number of ports, includinga camera port 116, one or more illumination ports 118, an access port orworking channel lumen 120, and a directional flush port 122.

Fitted within the camera port 116 is an image sensor (not shown) thatpreferably comprises a CMOS imaging sensor or other solid state deviceand one or more glass or polymeric lenses that produce electronicsignals representative of an image of the tissue in front of the cameraport 116. The image sensor is preferably a low light sensitive, lownoise video VGA, CMOS, color imager or higher resolution sensor such asSVGA, SXGA, or XGA. The video output of the sensor may be in anyconventional format including PAL, NTSC or high definition video format.

The illumination port 118 houses one or more lenses and one or morelight emitting diodes (LEDs) (not shown). The LEDs may be high intensitywhite light sources or may comprise colored light sources such as red,green and blue LEDs. With colored LEDs, images in different spectralbands may be obtained due to illumination with any one or moreindividual colors. White light images may be obtained by thesimultaneous or sequential illumination of the colored LEDs andcombining individual color images. As an alternative to LEDs, the lightsource may be external to the endoscope and the illumination lightdelivered to the illumination port with a fiber optic bundle.

The access port 120 is the termination point of the working channel orlumen of the endoscope 20. In the embodiment described above, theproximal end of the working channel terminates at the breakout box 26 asshown in FIG. 2. However, the working channel could terminate nearer theproximal end of the imaging catheter.

The directional flush port 122 includes a cap 124 that directs liquidsupplied through an irrigation and insufflation lumen across the frontface of the distal tip 110 in the direction of the camera port 116and/or the illumination port 118. The cap 124 thereby serves to cleanthe camera port 116 and the illumination port 118 for a better view ofthe internal body cavity in which the imaging catheter is placed. Inaddition, the flushing liquid cleans an area of tissue surrounding thedistal end of the endoscope.

FIG. 7 shows further detail of one embodiment of a distal tip 110 of theimaging endoscope. In this embodiment, the tip section 110 includes anumber of counter bored holes 126 that are positioned around thecircumference of the distal tip 110. The counter bored holes 126 receiveswaged or flanged ends of the control cables that orient the distal tip.Tension on the control cables pull the distal tip 110 in the directionof the tensioning force.

FIG. 8 is a lengthwise, cross-sectional view of an imaging endoscope 20in accordance with one embodiment of the present invention. The distaltip 110 is adhesively secured, welded or otherwise bonded within acenter lumen at the distal end of the articulation joint 30. Secured tothe proximal end of the articulation joint 30 is a distal end of a shaft128. As discussed above, the shaft 128 is preferably stiffer or betterable to transmit torque towards the distal end of the endoscope than atthe proximal end of the endoscope.

The control cables 130 that move the distal tip of the endoscope arepreferably made of a non-stretching material such as stainless steel ora highly oriented polyethylene-theralate (PET) string. The controlcables may be routed within a center lumen of the shaft 128 or, as shownin FIG. 8, may be routed through lumens formed within the walls of theshaft. The control cables 130 extend through guides within the walls ofarticulation joint 30 and terminate either at the distal end of thearticulation joint 30 or in the distal tip section 110.

If the control cables are routed through the center lumen of the shaft128, the cables are preferably carried in stainless steel or plasticspiral wrapped lumens to prevent binding and a transition guide 140 suchas that as shown in FIGS. 9A and 9B may be used to guide the controlcables into the proximal end of the articulation joint. The transitionguide 140 has a proximal end 142 that is secured within a lumen of thedistal end of the shaft. A central body portion 144 of the transitionguide 140 has a diameter equal to the outer diameter of the imagingendoscope. In addition, the body portion 144 includes a number ofdiagonal lumens 148 that extend from a center lumen of the proximal end142 to an outer surface of a stepped distal end 146 of the transitionguide. The distal end 146 is secured within a proximal end of thearticulation joint 30. Control cables in the diagonally extending lumens148 are therefore guided to the outer edge of the catheter where theyextend through the guides or control cable lumens of the articulationjoint 30.

FIGS. 10A, 10B illustrate one embodiment of a shaft that comprises theimaging endoscope 20. The shaft 160 has a cover 162 that may include awire or other braid 164 embedded therein. The braid 164, if present,allows the torque characteristics of the shaft to be adjusted. The cover162 may be formed by placing a sleeve over a mandrel. The braid 164 isplaced over the sleeve and the mandrel is dipped into or sprayed with acoating material. Preferably the sleeve and coating material are made ofpolyurethane or other biocompatible materials such as polyethylene,polypropylene or polyvinyl alcohol. In addition, the interior lumen(s)and exterior of the shaft can be coated with a extrudable, hydrophilic,lubricious coating such as the HYDROPASS™ hydrophilic coating availablefrom Boston Scientific, of Natick, Mass., and described in U.S. Pat.Nos. 5,702,754 and 6,048,620 which are herein incorporated by reference.

A plastic spiral wrap 166 such as spiral wire wrap available fromPanduit Inc. is inserted into a lumen of the cover 162. The spiral wrap166 prevents the shaft 160 from crushing as it is bent around apatient's anatomy.

In one embodiment of the shaft 160, the spiral wrap has a thickness of0.060 inches and a pitch of 3/16 inch. However, it will be appreciatedthat other thicknesses of spiral wrap with a different pitch could beused to provide the desired column strength and bend modulus as well asto prevent kinking.

FIG. 11 shows one method of altering the torque fidelity of the distaland proximal portions of the shaft. The shaft 160 has a flexible section170 that is proximal to the break out box and a stiffer section 172 thatis distal to the break out box. The portion of the scope that is distalto the break out box has an increasing flexibility toward the distal tipand conversely a higher torque fidelity and column strength proximally.To increase the torque fidelity characteristics of the distal section172 of the shaft, a braid 164 in that section includes two or more wiresthat are wound in opposite directions. In one embodiment, the wire braidhas a pitch of 14-16 pik. However, the number of wires and their spacingcan be adjusted as needed in order to tailor the torque fidelity of theshaft.

The proximal end 170 of the shaft 160 has a single spiral of wire 176that is preferably wound in the same direction as the plastic spiralwrap 166 in the center lumen of the shaft 160. Again, the torquefidelity of the proximal end of the shaft 170 can be adjusted byadjusting the pitch and/or direction of the wire 176 and itsflexibility.

As will be appreciated, the single wire spiral 176 provides some torquefidelity but does have the same torque fidelity as the dual wire braidin the distal section of the shaft. The single wire spiral 176 may beomitted from the proximal portion of the shaft if even less torquefidelity is desired.

In order to facilitate steering the distal tip of imaging endoscope, theendoscope includes an articulation joint that allows the distal tip tobe turned back on itself, i.e., over an arc of 180 degrees, by thecontrol cables. As shown FIG. 12A, 12B[,?] an articulation joint 200 isformed from a cylinder of a plastically deformable material having acentral lumen 202, and a number of control wire lumens 204 located inthe walls of the articulation joint. If desired, the space between thecontrol wire lumens in the cylinder wall may be thinner such that thecontrol wire lumens form bosses that extend into the central lumen ofthe cylinder. The control cable lumens 204 are preferably oriented at120° apart if three control cables are used or 90° apart if four controlcables are used.

To facilitate bending of the articulation joint, the cylinder includes anumber of live hinges 220 formed along its length. As can be seen inFIG. 13, each live hinge 220 comprises a pair of opposing V-shaped cuts230 on either side of the cylinder and are separated by a flexible web232 that forms the bendable portion of the hinge. In the embodimentdesigned for four control cables, each live hinge is oriented at 90degrees with respect to an adjacent hinge.

Upon retraction of a control cable, those live hinges having webs 232that are in line with the retracting control cable do not bend. Thoselive hinges having webs that are not in line with the control cable willbe closed, thereby bending the articulation joint in the direction ofthe control cable under tension.

Another advantage of the articulation joint shown in FIG. 13 is that thedistal end of the scope can be retracted by pulling all the controlcables simultaneously. This allows the physician to maneuver the distaltip in the body without having to move the remaining length of theendoscope. This may be useful when performing surgical procedures suchas obtaining a biopsy or snaring polyps.

The articulation joint can be formed by extruding a cylinder with thecentral and control cable lumens in place and cutting the cylinder tubewith a knife, laser, water jet, or other material removal mechanism toform the live hinges. Alternatively, the articulation joint can bemolded with the live hinge joints in place. As will be appreciated, theangles of the V-shaped cuts that form the hinges may be uniform or mayvary along the length of the articulation joint. Similarly, the distancebetween adjacent live hinges may be uniform or may vary in order totailor the bending and torque fidelity characteristics of thearticulation joint. In one embodiment of the invention, each live hingehas a closing angle of 30° so that six hinges are required to provide180° of movement. The distal end of the articulation joint 200 may becounter-bored to receive the distal tip section 110 of the endoscope, asdiscussed above. Similarly, the proximal end of the articulation joint200 is adapted to receive the distal end of the shaft of the endoscope.In the embodiment shown in FIG. 13, the control cable lumens 204 arealigned with the widest spacing of the live hinges and with the webportion of each hinge. However, it may be desirable to offset thecontrol cable lumens 204 with respect to the hinges in order to lessenpotential binding of the control cables in the hinge. As indicatedabove, the articulation joint should be made of a biocompatible materialthat will bend but will not collapse. Suitable materials includepolyurethane, polyethylene, polypropylene, or other biocompatiblepolymers.

To prevent wear by the control cables as they are pulled by theactuation mechanism in the motion control cabinet, it may be desirableto produce the articulation joint from a material having areas ofdifferent durometers. As shown in FIGS. 14 and 15, a cylinder formedfrom an extruded tube 240 has alternating bands of a high durometermaterial 242 and a lower durometer material 244 around itscircumference. The lumens 246 used to route the control cables areformed in the high durometer material to resist abrasion as the controlcables are tensioned and released. In addition, the high durometermaterial also reduces friction between the control cables and thesurrounding lumen. FIG. 15 illustrates an articulation joint where thecontrol cable lumens are offset with respect to the orientation of theweb portions 248 of the live hinges so that the control cables do notpass through the web portion of the hinge.

FIGS. 16A, 16B illustrate an alternative embodiment of an articulationjoint. In this embodiment, the joint comprises a series of ball andsocket connectors that are linked together. As shown in FIG. 16A, eachconnector includes a socket section 290 and a ball section 292. The ballsection 292 fits in a socket section 290 of an adjacent connector. Alumen 294 extends axially through the ball section 292 to allow forpassage of the wires that connect to the light source and the imagesensor and tubes that carry irrigation fluids and insufflation gases.The ball and socket sections are preferably molded of a biocompatiblepolymer.

Each socket section can be formed with a fully formed ball section suchas ball section 300 shown in FIG. 17A. Alternatively, a partial ballsection such as ball section 304 can be formed on a socket section 306as shown in FIG. 17B. To provide room for the control cables to move,the ball section can include slot 308 as shown in FIGS. 17A, 17B thatcuts through the middle and sides of the ball section. Alternatively, anumber of smaller slots 310 can be positioned around the circumferenceof the ball section as shown in FIGS. 17C and 17D. The slots allow thecontrol cables to be shortened under tension. A number of holes 312 atthe interface of the ball section and socket section allows passage ofthe control cables from the socket section into the ball section asshown in FIG. 17D.

In another embodiment of an articulation joint, the joint is made of aseries of stacked discs that are positioned adjacent one another andmove with respect to each other. As shown in FIG. 18A, a disc 350comprises an annular ring 352 having a pair of rearward facing rockersurfaces or cams 354 and a pair of forward facing rocker surfaces orcams 356. The cams 354 are positioned 180° apart on the rear surface ofthe annular ring 352, while the forward facing cams 356 are positioned180 degrees apart on the forward face of the annular ring 352. In theembodiment shown, the forward cams 356 are oriented at 90° with respectto the rear cams 354. Opposite each cam on the other side of the annularring is a flat land section so that the cams of an adjacent disc mayengage with and rock on the flat section. Holes 360 are drilled throughthe annular ring and through the cams for passage of the control cables.Upon tension of the control cables, the discs will rock on the surfaceof the cams 354, 356 thereby bending the articulation joint in thedesired direction.

FIG. 18B shows an articulation joint made up of a series of stackeddiscs 350 a, 350 b, 350 c . . . engaged with one another to form anarticulation joint. A number of control cables 370 a, 370 b, 370 c, 370d, pass through the discs and are used to pull the discs on the camsurfaces to move the joint in the desired direction.

FIGS. 19A and 19B show an alternative embodiment of the articulationjoint shown in FIGS. 18A and 18B. In this embodiment, an articulationjoint comprises a series of stacked discs 380, each comprising anannular ring having a pair of concave pockets 382 on its rear surfaceand a pair of correspondingly shaped convex cams 384 on its frontsurface. The concave pockets 382 are oriented at 90° with respect to theconvex cams 384 so that adjacent discs may be stacked such that the camsof a disc fit within the pockets of the adjacent disc. The correspondingshaped cams 384 and pockets 382 help prevent the discs from rotatingwith respect to one another. Holes or lumens 386 are formed through theannular ring 380 for passage of a number of control cables 390 a, 390 b,390 c, 390 d, as shown in FIG. 19B. The holes or lumens 386 may bepositioned at the center of the cams and pockets. However, the holes forthe control cables may be offset from the position of the cams andpockets, if desired. Preferably discs 380 are molded from abiocompatible polymer having a relatively slick surface, such aspolyurethane, polypropylene, or polyethylene, that reduces frictionbetween adjacent cams and pockets.

FIGS. 20A and 20B show yet another alternative embodiment of anarticulation joint. In this embodiment, the articulation joint is formedof a stack of discs, each of which comprises an annular ring. Theannular ring has cams having an arcuate slot 392 molded therein thatallows a control cable to move more freely in the cam as the disc ismoved relative to an adjacent disc. As best shown in FIG. 20B, the slot392 tapers from a widest point 394 at the outer edge of the cam to anarrow point 396 where the slot forms a cylindrical hole 398 thatextends to the opposite edge of the annular ring 380. A control wire 390b is free to bend within the widened portion of the arcuate slot 392 asan adjacent disc is rotated.

Although the discs of the articulation joints shown in FIGS. 18-20 aregenerally circular in shape, it will be appreciated that other shapescould be used. FIGS. 21A and 21B show an articulation joint formed froma number of sections having a generally square outer shape. As shown inFIG. 21A, a section 400 is a square band having a pair of pins 402 thatextend outwardly on opposite sides of the rear surface of the squaresection. On the opposite sides of the front surface are a pair ofopposing circular recesses 404 that are sized to receive the round pins402 of an adjacent section. The embodiment shown, the control cables arerouted through holes or lumens in corner blocks 406 that are found ineach corner of the square section 400. FIG. 21B shows two adjacentsquare sections 400 a, 400 b secured together. As can be seen, thesection 400 b can rotate up or down on its pins with respect to theadjacent section 400 a. Although circular and square articulationsections have been shown, it will be appreciated that other segmentshapes such as triangular or pentagonal, etc., could also be used toform an articulation joint.

In some environments, a full 180° turning radius of the distal tip ofthe imaging endoscope may not be necessary. In those environments, thearticulation joint may be replaced with a flexible member such as abraided stent. FIG. 22 shows an imaging endoscope 425 having a braidedstent 430 as the articulation joint. The braided stent extends between adistal tip 432 and a connector 434 that joins the proximal end of thestent 430 with the distal end of a flexible shaft 436. A cover 438extends over the flexible shaft 436 and the braided stent 430. Controlcables (not shown) extend through a lumen of flexible shaft 436 and areused to pull the stent 430 such that the distal tip 432 is oriented inthe desired direction. In addition, pulling all the control cablessimultaneously allows the distal tip of the endoscope to be retracted.

FIG. 23 shows one method of securing the distal ends of the controlcables to a braided stent 430. The control cables 440 a, 440 b, 440 c,440 d can be woven through the wires of the stent 430 and terminated byforming loops around the wires that comprise the stent. Alternatively,the ends of the cables 440 can be soldered or adhesively secured to thewires of the stent.

In some embodiments, the articulation joint is designed to exert arestoring force so that imaging endoscope will tend to straighten uponthe release of tension from the control cables. In other cases, it maybe desirable to maintain the position of the distal tip in a certaindirection. In that case, a construction as shown in FIG. 24 can be used.Here, the shaft of the imaging endoscope includes an inner sleeve 450that is overlaid with two or more plastic spiral wraps 452, 454, and456. Wrap 452 is wound in the clockwise direction while wrap 454 iswound in the counter-clockwise direction over the wrap 452 and the wrap456 is wound in the same direction as the first wrap 452. The wraps areformed of a relatively coarse plastic material such that friction iscreated between the alternatingly wound layers of the wrap. A suitablematerial for the plastic wrap includes a braided polyester orpolyurethane ribbon. Upon tension of the imaging endoscope by any of thecontrol cables, the plastic spiral wraps will move with respect to eachother and the friction between the overlapping wraps will tend tomaintain the orientation of the imaging endoscope in the desireddirection. The endoscope will remain in the desired direction until itis pulled in a different direction by the control cables. Covering thealternatingly wound spiral wraps 452, 454, and 456 is a braid 458. Thebraid is formed of one or more plastic or wire threads wound inalternate directions. An outer sleeve 460 covers the braid 458 tocomplete the shaft.

FIG. 25 shows another alternative embodiment of a shaft constructionused in an imaging endoscope according to the present invention. Theshaft includes a cover sheath 470 having bands of a high durometermaterial 472 and a low durometer material 474 that alternate around thecircumference of the sheath 470. The high durometer material and lowdurometer materials form longitudinal strips that extend along thelength of the shaft. Within the sheath 470 is a plastic spiral wrap 474that prevents the shaft 470 from crushing as it is bent in a patient'sanatomy. The high durometer materials add to the torque fidelitycharacteristics of the shaft. The width of the high durometer materialstrips compared to the low durometer material may be adjusted inaccordance with the torque fidelity characteristics desired.

During examination with the imaging endoscope, the physician may need totwist the scope in order to guide it in the desired direction. Becausethe outer surface of the scope is preferably coated with a lubricant andit is round, it can be difficult for the physician to maintain anadequate purchase on the shaft in order to rotate it. As such, theimaging endoscope of the present invention may include a grippermechanism that aids the physician in grasping the shaft for eitherrotating it or moving the shaft longitudinally. One embodiment of ashaft gripping device is shown in FIG. 26. Here, a gripper 500 comprisesa u-shaped member having a pair of legs 502, 504 that are aligned withthe longitudinal axis of an imaging endoscope 20. At the distal end ofthe legs 502, 504 are two 90° bends 506, 508. The gripper 500 includes ahole 505 positioned at the curved bent portion of the gripper that joinsthe legs as well as holes in each of the 90° sections 506, 508. Theimaging endoscope passes through the holes such that the gripper 500 isslideable along the length of the shaft portion of the endoscope. Thespring nature of the material used to fashion the gripper causes thelegs 502, 504 to be biased away from the shaft of the endoscope. Onlythe friction of the opposing holes at the bent portions 506, 508 preventthe gripper 500 from freely sliding along the length of the shaft. Onthe inner surface of the legs 502, 504 are a pair of touch pads 510,512, having an inner surface that is shaped to match the outercircumference of the shaft portion of the endoscope. When the physiciansqueezes the legs 502, 504 radially inward, the touch pads 510, 512engage the shaft such that the physician can push or pull the endoscopeor rotate it. Upon release of the legs 502, 504, the touch pads 510, 512release from the surface of the shaft and the gripper 500 can be movedalong the length of the shaft to another location if desired.

FIG. 27 shows a gripper similar to that of FIG. 26 with like parts beingidentified with the same reference numbers. In this embodiment, thegripper includes two hemispherical discs 520, 522, positioned on theoutside surface of the legs 502, 504. The hemispherical surfaces 520,522 are designed to fit within the hand of the physician and increasethe radial distance from the gripper to the shaft such that it is easierto twist the shaft, if desired.

FIG. 28 shows yet another alternative embodiment of a shaft gripper. Inthis example, a gripper 550 comprises a u-shaped member having a pair oflegs 552, 554, that are oriented perpendicularly to the longitudinalaxis of the imaging endoscope 20. The legs 552, 554 include a recessedsection 556, 558 that is shaped to receive the outer diameter of theshaft portion of the endoscope. A thumbscrew 560 is positioned at thedistal end of the legs such that the legs can be drawn together andcause the legs 554, 556 to securely engage the shaft of the endoscope.Upon release of the thumbscrew 560, the legs 554, 552 are biased awayfrom the shaft such that the gripper 550 can be moved. The shaft can betwisted by rotating the legs 552, 554, with respect to the longitudinalaxis of the shaft.

FIG. 29 shows an alternative embodiment of the gripper 550 shown in FIG.28. In this example, the gripper 580 includes a u-shaped member having apair of legs 582, 584. At the distal end of each leg is a recess 586,588 that is shaped to receive the outer diameter of the shaft. The shaftis placed in the recesses 586, 588, and a thumbscrew is positionedbetween the ends of the legs 582, 584, and the u-shaped bend in thegripper 580. By tightening the thumbscrew 590, the legs are compressedagainst the shaft of the imaging endoscope 20, thereby allowing thephysician to rotate the endoscope by moving the gripper 580.

In one embodiment of the invention the endoscope has a movable sleevethat operates to keep the distal end of the endoscope clean prior to useand covers the end of the scope that was in contact with a patient afterthe scope has been used.

FIGS. 30A and 30B illustrate one embodiment of an endoscope 594 having asponge 504 at its distal end. The sponge fits over the endoscope and hasa peel off wrapper that may be removed and water or other liquid can beapplied to the sponge. The water activates a hydrophilic coating so thatthe distal end of the endoscope has an increased lubricity. In addition,the sponge functions as a gripper when compressed allowing the physicianto pull and/or twist the endoscope.

A collapsible sleeve 598 is positioned over the distal end of theendoscope and can be retracted to expose the lubricated distal tip ofthe probe. In one embodiment, the sleeve 598 is secured at its distalend to the sponge 594 and at its proximal end to the breakout box.Moving the sponge proximally retracts the sleeve so that the endoscopeis ready for use. After a procedure, the sponge 594 is moved distally toextend the sleeve over the distal end of the endoscope. With the sleeveextended, any contaminants on the probe are less likely to contact thepatient, the physician or staff performing the procedure.

In some instances, it may be desirable to limit the amount of heat thatis dissipated at the distal end of the imaging endoscope. If lightemitting diodes are used, they generate heat in the process of producinglight for illumination. Similarly, the image sensor generates some heatduring operation. In order to limit how hot the distal end of theendoscope may become and/or to provide for increased life for thesecomponents, it is necessary to dissipate the heat. One technique fordoing so is to fashion a heat sink at the distal tip of the imagingendoscope. As shown in FIG. 31, a distal tip 600 includes a cap 602 anda heat dissipating section 604 that is made of a heat dissipatingmaterial such as a biocompatible metal. The heat dissipating section 604includes a semicircular opening 606 having a relatively flat base 608that extends approximately along the diameter of the heat dissipatingsection 604. The flat base 608 forms a pad upon which electricalcomponents such as the LEDs and image sensor can be mounted with athermally conductive adhesive or other thermally conductive material.The heat generating devices will transfer heat generated duringoperation to the heat dissipating section 604. The distal cover 602covers the distal end of the heat dissipating section 604 in order toprevent the heat dissipating section 604 from touching the tissue in thebody as well as to protect the body as the imaging catheter is moved inthe patient. Prisms, lenses, or other light bending devices may beneeded to bend light entering the distal end of the endoscope to anyimaging electronics that are secured to the relatively flat base 608 ofthe heat dissipating section 604.

FIG. 32 shows a heat dissipating distal tip of an endoscope wherein thedistal tip does not include a cover but is molded from a single piece ofheat dissipating material such as a biocompatible metal. The heatdissipating section 620 again includes a semicircular opening with arelatively flat surface 622 that extends along the diameter of thesection and on which heat generating electronic devices can be mounted.With a semicircular opening formed in the distal end of the heatdissipating distal tip 620, the illumination mechanism and image sensorare mounted on the flat surface 622. The irrigation port is oriented todirect water over the hemispherical cutout in order to clean theillumination mechanism and image sensor or image sensor lenses.

In yet another embodiment of the invention, the imaging devices at thedistal end of the endoscope can be cooled by air or water passed througha lumen to the end of the endoscope and vented outside the body. Forexample, air under pressure may be vented through an orifice near theimaging electronics. The expansion of the air lowers its temperaturewhere it cools the imaging electronics. The warmed air is then forced tothe proximal end of the endoscope through an exhaust lumen.Alternatively, the endoscope may include a water delivery lumen thatdelivers water to a heat exchanger at the distal tip. Water warmed bythe electronic components in the distal tip is removed in a water returnlumen.

FIG. 33 shows an alternative embodiment of the heat dissipating distaltip shown in FIG. 31. In this example, the heat dissipating distal tip640 has a number of scalloped channels 642 positioned around thecircumference of the distal tip. The scalloped channels 642 increase thesurface area of the heat dissipating distal tip, thereby furtherincreasing the ability of the tip to dissipate heat from theillumination and imaging electronic devices.

Although the present endoscopic imaging system has many uses, it isparticularly suited for performing colonoscopic examinations. In oneembodiment, a 10-13 mm diameter prototype having a 0.060 inner spiralwrap with a pitch of ¼ inch and coated with a hydrophilic coating wasfound to have a coefficient of friction of 0.15 compared to 0.85 forconventional endoscopes. In addition, the endoscope of the presentinvention required 0.5 lbs. of force to push it through a 2-inchU-shaped bend where a conventional endoscope could not pass through sucha tight bend. Therefore, the present invention allows colonoscopes to bemade inexpensively and lightweight so that they are more comfortable forthe patient due to their lower coefficient of friction and bettertrackability.

In addition to performing colonoscopies, the endoscopic imaging systemof the present invention is also useful with a variety of surgicaldevices including: cannulas, guidewires, sphincterotomes, stoneretrieval balloons, retrieval baskets, dilatation balloons, stents,cytology brushes, ligation devices, electrohemostasis devices,sclerotherapy needles, snares and biopsy forceps.

Cannulas are used with the endoscopic imaging system to cannulate thesphincter of Odi or papilla to gain access to the bile or pancreaticducts. Guidewires can be delivered down the working channel of theendoscope and used as a rail to deliver a surgical device to an area ofinterest. Sphincterotomes are used to open the papilla in order to placea stent or remove a stone from a patient. Stone retrieval balloons areused along with a guidewire to pull a stone out of a bile duct.Retrieval baskets are also used to remove stones from a bile duct.Dilatation balloons are used to open up strictures in thegastrointestinal, urinary or pulmonary tracts. Stents are used to openup strictures in the GI, urinary or pulmonary tracts. Stents can bemetal or plastic, self-expanding or mechanically expanded, and arenormally delivered from the distal end of a catheter. Cytology brushesare used at the end of guidewires to collect cell samples. Ligationdevices are used to ligate varices in the esophagus. Band ligatorsemploy elastic bands to cinch varices. Electrohemostasis devices useelectrical current to cauterize bleeding tissue in the GI tract.Sclerotherapy needles are used to inject coagulating or sealingsolutions into varices. Snares are used to remove polyps from the GItract, and biopsy forceps are used to collect tissue samples.

Examples of specific surgical procedures that can be treated with theendoscopic imaging system of the present invention include the treatmentof gastroesophageal reflux disease (GERD) by the implantation of bulkingagents, implants, fundoplication, tissue scarring, suturing, orreplacement of valves or other techniques to aid in closure of the loweresophageal sphincter (LES).

Another example of a surgical procedure is the treatment of morbidobesity by deploying implants or performing reduction surgery, gastricbypass and application or creating tissue folds to help patients loseweight.

Endoscopic mucosal resection (EMR) involves the removal of sessilepolyps or flat lesions by filling them with saline or the like to liftthem prior to resection. The endoscope of the present invention can beused to deliver needles, snares and biopsy forceps useful in performingthis procedure.

In addition, the endoscopic imaging system of the present invention canbe used to perform full-thickness resection (FTRD) in which a portion ofa GI tract wall is excised and the wounds healed with staplers orfasteners. Finally, the endoscopic imaging system of the presentinvention can be used to deliver sclerosing agents to kill tissues ordrug delivery agents to treat maladies of internal body tissues.

While the preferred embodiment of the invention has been illustrated anddescribed, it will be appreciated that various changes can be madetherein without departing from the scope of the invention. For example,although some of the disclosed embodiments use the pull wires tocompress the length of the endoscope, it will be appreciated that othermechanisms such as dedicated wires could be used. Alternatively, aspring can be used to bias the endoscope distally and wires used tocompress the spring thereby shortening the length of the endoscope.Therefore, the scope of the invention is to be determined from thefollowing claims and equivalents thereof.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:
 1. An articulation jointfor use in a steerable medical device, comprising a number of stackedannular rings, each ring having a pair of convex cams extendingoutwardly from a first surface of the ring and a pair of inwardlyextending concave pockets positioned on a second surface of the ringsuch that the convex cams of an adjacent annular ring fit within theconcave pockets.
 2. The articulation joint of claim 1, wherein theannular rings include holes for the passage of control cables.
 3. Thearticulation joint of claim 2, wherein the holes are aligned with theconvex cams and concave pockets.
 4. The articulation joint of claim 2,wherein the holes are offset from the convex cams and concave pockets.5. The articulation joint of claim 3, wherein the holes extendingthrough the convex cams form a slot at the edge of the convex cams. 6.The articulation joint of claim 5, wherein the holes have a flared shapewith a first width on a side of the annular ring opposite a convex camand a width that expands to form the slot as the hole extends throughthe convex cam.
 7. The articulation joint of claim 1, wherein eachannular ring is made of a polymer.
 8. The articulation joint of claim 7,wherein the polymer is one of the polyurethane, polypropylene, orpolyethylene.
 9. An articulation joint in a steerable medical device,comprising a number of cylindrical rings having a first rim and a secondrim, wherein each ring includes a pair of convex camming surfacespositioned 180° apart on one of the first or second rims and a pair ofconcave recesses positioned 180° apart on the other of the first orsecond rims, wherein a portion of the convex camming surfaces fits withthe concave recesses of an adjacent ring.
 10. The articulation joint ofclaim 9, wherein each of the cylindrical rings are made of polymer. 11.The articulation joint of claim 9, wherein the cylindrical rings includetwo or more holes passing axially through the ring.
 12. The articulationjoint of claim 11, wherein the holes pass through the convex cammingsurfaces and the concave recesses.
 13. The articulation joint of claim12, wherein the holes have a width that increase in size within theconvex camming surface such that the holes form an elongated slot at anedge of the convex camming surfaces.
 14. The articulation joint of claim9, wherein the convex camming surfaces on a ring are oriented at 90°with respect to the concave recesses on the same ring.